In many internal combustion engines, a hot-film air-mass sensor is used to measure the air mass flow flowing into an internal combustion engine. The diagnosis of the hot-film air-mass sensor takes place via a plausibility check of the air mass flow, which is measured by the hot-film air-mass sensor, via a comparison to an air mass flow modeled in dependence upon a throttle flap angle and the engine rpm. The requirements as to the plausibility check increase when an electrically-operated compressor is built into the air supply, that is, into the intake system of the engine.